With the development of the communication technology and the peoples' increasing insight into the trunking system, the trunking system, as an efficient emergency command scheduling system, plays a more and more important role. A trunking communication system is widely applied in the fields of government sectors, public security, emergency communication, electric power, civil aviation, petrochemical industry and military and so on. The development of the trunking system goes through stages of an analog trunking system and a narrowband digital trunking system, wherein many drawbacks exist in both two stages of the trunking systems, and the analog trunking system has disadvantages of large interference, many blind zones and limited frequency and so on, and with regard to the narrowband digital trunking system, even though it has improvement in the quality and capacity of communication relative to the analog trunking system, it is still weak in the aspects of data transmission capability and capability for supporting multimedia services, moreover, the narrowband digital trunking system has certain difficulties in evolving to the Long Term Evolution (LTE)-based broadband digital trunking system.
At present, the LTE-based broadband digital trunking system has become a development direction of the next generation trunking system, the related standard studies on the LTE-based broadband digital trunking system are being carried out domestically, and operators and enterprises wish to perform corresponding modifications or extensions as far as possible so as to complete the deployment of the LTE-based broadband digital trunking system based on the current existing LTE network and technology, thus not only the related LTE network and technology can be better utilized, but also the input costs are minimized for the operators and enterprises. Therefore, how to utilize the existing LTE network and technology to deploy a framework of the LTE-based broadband digital trunking system and to implement the application for speaking right of trunking services also becomes a problem required to be solved urgently.